Insulated curtain wall construction

ABSTRACT

AN INSULATED CURTAIN WALL CONSTRUCTION COMPRISING A METAL PANEL-BACKING MEMBER ADJUSTABLY JOINED BY THERMALLY INSULATED CONNECTOR MEANS TO A METAL PANEL-RETAINING MEMBER, A PANEL DISPOSED BETWEEN SAID BACKING AND RETAINING MEMBERS AND INSULATING GLAZING MATERIAL DISPOSED BETWEEN SAID PANEL AND SAID BACKING AND RETAINING MEMBERS WHEREBY THE PANEL-BACKING MEMBER AND PANELRETAINING MEMBER ARE EACH INSULATED FROM THE OTHER AND FROM SAID PANEL MEMBER DISPOSED THEREBETWEEN.

Jan. 12, 1971 5 DAUSQN 3,553,918

INSULATED CURTAIN WALL CONSTRUCTION Original Filed Sent. 28, 1967 5 sheets-sheet 1 INVENTOR SAMUEL DA 5 0N BY Li ewfi g mme,

ATTORNEYS Jan. 12, 1971 s. DAUSQN 3,553,918

INSULATED CURTAIN WALL CONSTRUCTION Original Filed Sept. 28, 1967 5 Sheets-Sheet 5 INVENTOR I 6AMuEL oAusoxv @isW Jam, 12, 1971 s. DAUSON NSULATED CURTAIN WALL CONSTRUCTION 5 Sheets-Sheet 4 INVENTOR SAMUEL DAUSON Original Filed Sent. 2

ATTORNEYQ S. DAUSON JihI INSULATED CURTAIN WALL CONSTRUCTION 5 Sheets-Sheet 5 Original Filed Sent. 28, 1967 INVENTOR SAMUEL DAUS ATTORNEYS 3,553,918 INSULATED CURTAIN WALL CONSTRUCTION Samuel Dauson, Pittsburgh, Pa., assignor to PPG Industries, Inc., Pittsburgh, Pa., a corporation of Pennsylvanra Continuation of abandoned applications Ser. No. 671,302, Sept. 28, 1967, and Ser. No. 688,792, Dec. 7, 1967. This application July 22, 1969, Ser. No. 843,349

Int. Cl. E04b 2/88, 3/62 US. Cl. 52-395 22 Claims ABSTRACT OF THE DISCLOSURE CROSS-REFERENCE TO RELATED APPLICATIONS This application is a continuation of applications Ser. No. 671,302, filed Sept. 28, 1967, and Ser. No. 688,792, filed Dec. 7, 1967, both now abandoned, and complete disclosures of which are incorporated herein by reference and relied upon in the present application.

BACKGROUND OF THE INVENTION This invention relates to a wall construction and, in

particular, to a novel, insulated curtain wall construction.

In US. Pat. No. 3,336,707, assigned to the assignee of the present invention, there is disclosed an insulated curtain wall construction for mounting panels on a frame or grid structure comprising a T-shaped elastomeric structural glazing gasket having the body or arm portion of the gasket in supporting engagement with a panel, the leg portion of the gasket received in a mounting groove in a frame member and gasket engagement means supported within said groove and engaging the leg portion of the gasket to lock the assembly together.

In US. Pat. No. 3,435,579, also assigned to the assignee of the present invention, there is disclosed a further insulated wall construction for mounting panels comprising horizontal and vertical members interconnected to form a frame and wherein each frame member carries an outwardly directed flange on one common vertical face thereof, an elastomeric structural glazing gasket mounted on said flange to support a panel and insulating panelbacking strips disposed between said panel and said frame member.

In known forms of wall construction prior to the above inventions, various attempts were made to provide a thermal grid barrier, i.e., a thermal break in the grid or frame members, as well as a thermal break between the panel members and the grid or frame members, to prevent heat transfer from one member to another. However, none of these known forms of construction were found to be completely satisfactory.

Even with the advent of the above-mentioned inventions wherein for the first time completely satisfactory constructions were provided for producing both structurally and functionally sound thermal wall systems, these systems were nevertheless restricted in appearance and required maintaining close tolerances in the manufacture of their component parts. Each of the foregoing systems used an exposed elastomeric glazing gasket, the appearance of which in a composite wall assembly might not United States Patent O 3,553,918 Patented Jan. 12, 1971 always completely fulfill the aesthetic desires of the architect and/ or building owner. Moreover, each of the abovementioned systems might well be characterized as non-adjustable systems in that they contained no provision for field adjustment of components in order to positively obtain a water-tight and/ or structurally-tight wall. Accordingly, each of these systems required maintaining strict control over field erection and tolerance deviations in the manufacture of their component elements or parts. The present invention is directed to providing a solution to these latter-mentioned problems and, more specifically, to providing a thermally insulated wall system that is not hampered by tolerance considerations and that may be adapted to provide almost any desired appearance.

The present invention, like those disclosed in the aforementioned patents, combines all. of the best features of known types or forms of curtain wall construction and provides a novel curtain wall system that is structurally sound, that is relatively easy and inexpensive to install, that inherently possesses a complete thermal grid barrier, and that is comparable or lower in cost to any known form of wall construction.

In addition, the curtain wall system of the present invention, unlike those disclosed in the aforementioned patents, is adjustable to accommodate tolerance deviations and, accordingly, is not inherently or unduly hampered by tolerance considerations. Also, the curtain wall system of this invention permits wide versatility in the finish, color, shape and/ or appearance or depth of section of the panel-framing members by reason of employing cap or cover members that can be fabricated to provide practically any desired appearance.

Moreover, the basic curtain wall system of this invention can be completely reversed and thus can accommodate mounting the panels either from the interior or the exterior of the building for maximum freedom in design and installation.

Furthermore, the curtain wall system of the present invention provides a clean or uninterrupted sight line, particularly when viewing directly into the curtain wall. This is important both aesthetically and functionally where the system employs the use of transparent panels.

Novel features of the present invention that make the foregoing advantages possible involve the use of relatively low thermal conductivity material to separate and thermally isolate a metal panel-backing member relative to a spaced, opposed, metal panel-retaining member to which said backing member is threadably or adjustably joined. The metallic panel-backing member and panelretaining member are each spaced from an interposed panel member by means of insulating glazing material. Furthermore, the panel-retaining member is provided with suitable means to attach thereto a wide variety of cover members.

The foregoing and other features and advantages of this invention will be better understood when reference is had to the accompanying drawings, in which:

FIG. 1 represents an outside elevation of a typical curtain wall constructed in accordance with the present invention;

FIG. 2 is a typical cross-section along the line AA of FIG. 1 showing the details of vertical framing mernbers constructed in accordance with one preferred embodiment of the present invention;

FIG. 3 is a typical cross-section along the line B-B of FIG. 1 showing the details of horizontal framing members constructed in accordance with said one preferred embodiment of the present invention;

FIG. 4 is a typical cross-section. along the line AA of FIG. 1 showing details of vertical framing members c nstructed in accordance with a second preferred embodiment of the present invention; and

FIG. is a typical cross-section along the line BB of FIG. 1 showing details of horizontal framing members constructed in accordance with said second preferred embodiment of the present invention.

The curtain wall 10, depicted in FIG. 1, consists of a plurality of panels 12, which are separated and supported along their peripheral edges by horizontal and vertical panel-framing members or grid members 14 and 16 of substantially identical cross-section. The frame members shown at 16 in FIGS. 2 and 4 are split members. Split members are frequently employed to accommodate expansion in the walls of a building. For the urpose of the present invention, however, each of the frame members 16' may also be a one-piece extrusion or each may be a sectionalized member of cross-sectional configuration somewhat different than that shown in FIGS. 2. and 4. In addition, unitary and/ or sectionalized frame members can be used in any desired combination.

Although FIG. 1 is intended to show horizontal and vertical framing members suporting a plurality of panels covering a complete wall section, it will be appreciated from the following description that the present invention is equally Well adapted to single or multiple panel constructions. The panels 12 may be of an insulating or noninsulating type and of any suitable material or construction.

Referring to FIG. 1, horizontal framing members 14 and vertical framing members 16 are joined to form a rigid structural frame or framework. With particular reference being had to the embodiment of FIGS. 2 and 3, the horizontal and vertical framing members 14 and 16 are each composed essentially of a metal panel-backing member 18 joined to a thermally insulated connector 22 which preferably comprises a rigid member of relatively low thermal conductivity material and which, in turn, is adjustably connected to a metal panel-retaining member 24. The metallic panel-backing member 18 and panelretaining member 24 are each spaced from an interposed panel member .12 by means of insulating glazing strips 26. The panel-retaining member 24, in the embodiment shown, is attached to connector member 22 by threadably adjustable screw fasteners 28 and, in addition, is provided with a pair of longitudinally extending ribs or flanges 30 over which a cover or cap member 32 is snapped into place.

Referring specifically to FIG. 2 for further details, panel-backing member 18 is an elongated structural member composed of a tubular or channel-shaped stiffening portion 34 that imparts rigidity and strength to the framing member and that carries thereon a panel-backing portion 36 which may be either a separate member joined to the stiffening portion or may be formed integrally with the stiffening portion 34.

In the embodiment shown, panel-backing portion 36 comprises a pair of integral flanges 38 extending from the stiffening portion 34 of the panel-backing member 18 and having a structure formed thereon, such as longitudinally extending flanges 40 that carry longitudinally extending grooves 42, adapted to support insulating glazing strips 26. Between longitudinally extending flanges 38 and 40 and stiffening portion 34, there is provided an inwardly directed, longitudinally extending mounting groove 44 which receives and retains one or more spring clips and one or more connector members 22. Thus, it is contemplated that spring clips 20 and/or connector members 22 may either be continuous members that are essentially coextensive with the length of mounting groove 44 or one or both may comprise members of relatively shorter length, e.g., 1 /2 to 4 inches, appropriately spaced along the length of mounting groove 44 and joined in assembled relation.

Mounting groove 44, as aforesaid, is formed by longitudinally extending flanges 38 and 40 and web 35 of stiffening portion 34 of the panel-backing member. Flat springs or spring clips 20 are held in place within mounting groove 44 by protrusions 21 and flanges 40 which provide means for positively resisting disengagement of spring clips 20 from mounting groove 44. Springs 20 provide connector engagement means for locking and retaining connector member 22 within mounting groove 44. The opening or access 46 into mounting groove 44 provided between flanges 40 provides means for extending connector member 22 forwardly or outwardly from the mounting groove 44 of panel-backing member 18.

Connector member 22 is a member of essentially uniform cross-section which, in the embodiment shown, has an interlocking or bulbous end portion 54, providing two protruding longitudinal lips 55. The protruding lips 55 snap into and lock with the flat springs 20 when the connector member 22 is inserted into groove 44 in the rigid frame formed by horizontal and vertical panel-framing members 14 and 16. It will be appreciated that the thickness of connector member 22 and bulbous end portion 54 is slightly less than the width of groove 44. This permits the connector member 22 to be readily inserted within groove 44 in the rigid frame formed by horizontal and vertical panel-framing members 14 and 16. Integrally formed with the interfitting and/ or interlocking portion 54 of connector member 22 is a stem portion 48 that extends forwardly and outwardly from flat springs 20 and has a screw groove 56 formed in its distal end for the purpose of securing thereto panel-retaining member 24.

Panel-retaining member 24 is essentially an elongated clip member extending the full length of each of the horizontal and vertical framing members and having formed on opposite longitudinal edges thereof a structure, such as grooves 58, adapted to support insulating grazing strips 26. Intermediate said longitudinal edges there is provided on said retaining member 24 a longitudinally extending boss 60, which in the installed position of retaining member 24 preferably is separated a short distance from the surface or distal end of connector member 22 that has formed therein the opening to screw groove 56. Suitable apertures (not shown) are provided in panel-retaining member 24 and extend through boss 60 for the purpose of adjustably securing panel-retaining member 24 to connector member 22 and relative to anel-backing member 18 by means of screw fasteners 28 extending through said apertures and received in screw groove 56. Also formed at or near the longitudinal edges of panel-retaining member 24, but on the side opposite that which is adapted to carry insulating glazing strips 26, are longitudinally extending flanges or ribs 30 over which a metal cover or cap member 32 is snapped and securely locked into place. Cover or cap members 32 can be of almost any desired shape, finish, color and depth of section. In the embodiment shown, cover member 32 is a U-shaped channel member having a web that presents a flat outer surface parallel to the curtain wall panels and a pair of flanges that present flat side surfaces which are coplanar with the side surfaces of the horizontal and vertical stiffening members.

The preferred method of assembly of the curtain wall construction of this embodiment of the invention involves inserting continuous spring clips 20 longitudinally into the mounting groove 44 in panel-backing member 18, erecting a plurality of panel-backing members into a rigid grid or frame of horizontal and vertical members; inserting connector member 22 into groove 44 far enough so that interlocking portion 54 snaps into and locks with spring clips 20; aflixing insulating strips 26 to the panel-backing members; setting a panel in place against each thus-formed frame of insulating strips; affixing insulating strips 26 to panel-retaining member 24; joining or securing a panel-retaining member 24 to each panel-backing member 18 by means of screw fasteners 28 being threadably received in screw groove 56 of connector member 22; and snapping cover member 32 over flanges or ribs 30 to provide the completed assembly.

It will be appreciated that, among other novel features, the foregoing construction of this invention provides a metal-faced, insulated curtain wall system having adjustable panel-retaining members to accommodate any buildup of tolerances in the panel-backing members, spring clips and connector members, and, accordingly, an insulated system that is not inherently or unduly hampered by tolerance considerations. Also, the curtain wall system of this invention permits wide versatility in the finish, color, shape and/or appearance of depth of section of the panel-framing members by reason of employing cap or cover members that can be fabricated to provide practically any desired finished appearance.

Referring now to the alternate preferred embodiment of this invention shown in FIGS. 4 and 5, the horizontal and vertical framing members 14 and 16 are each composed essentialy of a panel-backing member 118, an overlapping and interlocking plate or plate-like member 120, insulating spacer strips 122, a panel-retaining member 124 and a bolt 126 that threadably or adjustably aflixes panel-retaining member 124 to plate member 120. The metallic panel-backing member 118 and panel-retaining member 124 are each spaced from an interposed panel member 12 by means of insulating glazing beads 128. The panel-retaining member 124, in the embodiment shown, is also provided with a pair of longitudinally extendingribs or flanges 130 over which a cover or cap member 132 is snapped into place.

Referring specifically to FIG. 4 for further details, panel-backing member 118 is an elongated structural member composed of a tubular or channel-shaped stiffening portion 134 that once against imparts rigidity and strength to the framing member and that carries thereon a panel-backing portion 136 which may be either formed integrally with the stiffening portion 134 or a separate member joined to the stiffening portion 134.

In the embodiment shown, panel-backing portion 136 is formed integrally with stiffening portion 134 and comprises an elongated, generally U-shaped channel structure composed of the web 135 of stiffening portion 134, a pair of spaced flanges 138 extending forwardly or outwardly therefrom and a pair of flanges 140 that extend toward each other from the free ends of flanges 138. The free ends of flanges 140 are in opposed, spaced relation to each other. Each flange 140 has a structure formed on its forwardly or outwardly facing surface or side adapted to support an insulating glazing bead 128 and a structure formed on its opposite surface or side adapted to support an insulating spacer strip 122. Between longitudinally extending flanges 138 and 140 and web 135 of stiffening portion 134, there is provided a longitudinailly extending groove 144 which receives and retains one or more plate members 120 and one or more pairs of insulating spacer strips 122. Thus, it is contemplated that the plate members 120 and/or insulating spacer strips 122 may either be continuous members that are essentially coextensive with the length of groove 144 or one or both may comprise members of relatively shorter length, e.g. /2 inch to ,4 inches, appropriately spaced along the length of groove 144 and joined in assembled relation. Where it is desired to use sufficiently short lengths of plate member 120, such that the length of plate member 120' is less than both its width dimension and the spacing between the opposed free ends of flanges 140, it wil be apparent that plate member 120 may be inserted transversely into groove 144 and then rotated into its finally installed position. In any event, plate member 120 is of a lesser width than the width of groove 144 between flanges 138 so that, in its assembled position, there is no physical contact between plate member 120 and flanges 138.

Groove 144, as aforesaid, is formed by longitudinally extending flanges 138 and 140 and web 135 of stiffening portion 134 of panel-backing member 118. Opposed flanges 140 provide a restricted opening or restricted transverse access into groove 144, and thus comprise means for positively resisting disengagement of plate member from groove 144 when plate member 120 is in its finally installed position. The opening or access 146 into groove 144 provided between flanges also provides means for extending belt 126 forwardly or outwardly from the groove 144 of panel-backing member 11 8. As shown, access opening 146 is larger than the corresponding linear dimension of the proximate por-- tion of bolt 126 so that, in the installed position of the bolt 126, there is no physical contact between bolt 126 and panel-backing member 118.

In the embodiment shown, bolt 126 extends through an aperture (not shown) in panel-retaining member 124 and is threadably or adjustably joined with plate member 120 by means of a threaded aperture (not shown) provided therein. Also, as shown, insulating spacer strips 122 are mounted in grooves 148 in flanges 140. Spacer strips 122 are composed of natural or synthetic rubber or other insulating material having a relatively low thermal conductivity. Spacer strips 122 support plate member 120 in spaced relation to flanges 140.

As should be apparent, plate member 120 need not necessarily assume the precise shape shown. Furthermore, a toggle or other articulated member could be used in lieu of plate member 120. Also, it should be apparent that insulating spacer strips 122 need not be restricted to the precise shape or means of mounting illustrated. For example, spacer strip 122 could be a U-shaped member cemented to the longitudinal edges of plate member 120. Thus, it is contemplated by this invention that insulating material of any shape could be mounted onto or about or otherwise structurally associated with an overlapping and/or interlocking connector members so that the connector member joins a panelbacking and panel-retaining member in assembled relation and thermally isolates the backing and retaining members relative to each other. In addition, other fasteners than the bolt 126 shown could be used for the purpose of adjustably securing panel-retaining member 124 relative to panel-backing member 118. For example, a stud threaded on both ends or a stud threaded on one end and Welded or otherwise secured at its other end to plate member 120 could be used. In addition, a fastener or connector portion comprising an elongated flange formed integrally with plate member 120 and provided on its free end with a screw groove, aperture or the like could be used in combination with a screw extending through anaperture in panel-retaining member 124 to adjustably secure panel-retaining member 124 relative to panel-backing member 118. Thus, it is contemplated that any suitable connector means composed of and/or provided with relatively low thermal conductivity insulating means and falling within the range of equivalents of the specific embodiments shown could be used without departing from the spirit of this invention. It is only essential for the practice of this invention that the panel-backing and panel-retaining structural components be thermally insulated relative to each other, and that suitable provision be made for adjustably securing the panel-retaining member relative to the panel-backing member.

Panel-retaining member 124 is essentially an elongated clip member extending the full length of each of the horizontal and vertical framing members and having formed on opposite longitudinal edges thereof a structure, such as grooves 125, adapted to support insulating glazing beads 128. Intermediate said longitudinal edges, suitable apertures (not shown) are provided in panelretaining member 124 for the purpose of adjustably securing panel-retaining member 124 to panel-backing member 118 by means of bolt 126 extending through said apertures and received in threaded apertures (not shown) in plate 120. Also formed at or near the longitudinal edges of the panel-retaining member 124 but on the side opposite that which is adapted to carrying insulating glazing beads 128 are longitudinally extending flanges or ribs 130 over which a cover or cap member 132 of metal or other rigid material is snapped and securely locked into place. Cover or cap member 132 can be almost any desired shape, finished color and depth of section. In the embodiment shown, cover member 132 is a U-shaped channel member having a web that presents a flat outer surface parallel to the curtain wall panels and a pair of flanges that present flat side surfaces which are coplanar with the side surfaces of the horizontal and vertical stiffening members.

It will be appreciated from the foregoing that, among other novel features, this invention provides a versatile, metal-faced, insulated curtain wall structure having adjustable panel-retaining members to accommodate any buildup of tolerances in its component elements or parts and, accordingly, an insulated wall structure that is not inherently or unduly hampered by tolerance considerations. Also, the curtain wall system of this invention permits wide versatility in the finish, color, shape and/or appearance of depth of section of the panel-framing members by reason of employing cap or cover members that can be fabricated to provide practically any desired finished appearance.

While the preferred embodiments of this invention have been illustrated and described, it will be understood that various changes and modifications in the method of assembly and in the materials, structural shapes, arrangement of parts and components within the range of equivalents of those specifically mentioned may be made within the scope of the appended claims without departing from the spirit of the invention.

I claim:

1. An insulated curtain wall construction comprising a metal panel-backing member, a metal panel-retaining member, connector means comprising insulating material thermally isolating said backing member relative to said retaining member and adjusta'bly joining said backing and retaining members in assembled relation, a panel disposed between said backing and retaining members and insulating material disposed between said panel and one of said backing and retaining members whereby the panel-backing member and panel-retaining member are each insulated from the other and said panel is insulated from said one of said backing and retaining members.

2. An insulated curtain wall construction according to claim 1, wherein said panel-retaining member has means formed thereon for supporting a cover member and a channel-shaped cover member is aflixed to said cover member supporting means.

3. An insulated curtain wall construction according to claim 1 wherein said connector means comprises a connector member disposed between said backing and retaining members, connector engagement means carried on said backing member and securing a first portion of said connector member relative to said backing member, and adjustable fastening means carried on said retaining member and securing a second portion of said connector member relative to said retaining member.

4. An insulated curtain wall construction according to claim 3, wherein said panel-retaining member has means formed thereon for supporting a cover member and a channel-shaped cover member is aflixed to said cover member supporting means.

5. An insulated curtain wall construction according to claim 3 wherein said panel-backing member is an elongated structural member having a longitudinally extending channel-shaped stiffening portion that carries thereon a longitudinally extending panel-backing portion, and said panel-backing portion comprises a pair of flange members extending from said stiffening portion and defining therebetween a longitudinally extending mounting groove for receiving and retaining therein said first portion of said connector member, said flanges having means formed thereon to support insulating glazing strips.

6. An insulated curtain wall construction according to claim 5, wherein said panel-retaining member has means formed thereon for supporting a cover member and a channel-shaped cover member is aflixed to said cover member supporting means.

7. An insulated curtain wall construction according to claim 5 wherein said connector member is a longitudinally extending member having a first portion comprising an interlocking portion received and retained in said mounting groove and a second portion comprising a stem portion extending forwardly and outwardly of said groove and having means formed on its distal end for the purpose of securing thereto said panel-retaining member.

8. An insulated curtain wall construction according to claim 7, wherein said panel-retaining member has means [formed thereon for supporting a cover member and a channel-shaped cover member is aflixed to said cover member supporting means.

9. An insulated curtain wall construction according to claim 8 wherein the connector engagement means carried on said backing member comprises a longitudinally extending spring clip engaging said interlocking portion of said connector member.

10. An insulated curtain wall construction according to claim 9 wherein said adjustable fastening means is a threaded fastener joining said second portion of said connector member and said panel-retaining member.

11. An insulated curtain wall construction according to claim 10 wherein said panel-retaining member is a longitudinally extending member having means formed on opposite longitudinal edges thereof to support insulating glazing strips.

12. An insulated curtain wall construction according to claim 11 wherein said panel-retaining member has formed on the side thereof, opposite that which is adapted to carry insulating glazing strips, means for supporting a metal cover member and a metal cover member aflixed to said cover member supporting means.

13. A structural support for a curtain wall panel comprising horizontal and vertical members interconnected to form a frame, with each frame member having a longitudinal mounting groove and means formed on opposite longitudinal edges thereof to support insulating glazing strips, a longitudinally extending spring clip supported within said groove in locking engagement with a connector member comprising a longitudinally extending member having a first portion in interlocking engagement with said spring clip and a second portion extending forwardly and outwardly of said mounting groove and having formed on its distal end means for adjustably securing thereto a panel-retaining member, a panel-retaining member secured to said second portion of said connector member, said panel-retaining member having means formed on opposite longitudinal edges thereof to sup port insulating glazing strips, a panel disposed between said horizontal and vertical members and said panel-retaining members and insulating glazing material disposed between said panel and said frame members and between said panel and said panel-retaining members.

14. A structural support for a curtain wall panel according to claim 13, wherein said panel-retaining member has means formed thereon for supporting a cover member and a channel-shaped cover member is aflixed to said cover member supporting means.

15. A structural support for a curtain wall panel according to claim 13 wherein said panel-retaining member has formed on the sides thereof, opposite that which is adapted to carry insulating glazing strips, means for supporting a metal cover member and a U-shaped cover member having flat outer surfaces aflixed to said cover member supporting means.

16. A structural support for a curtain wall panel according to claim wherein said connector member comprises insulating material.

17. A structural support for a curtain wall panel according to claim 15 wherein each horizontal and vertical member and each channel-shaped cover member carried by said panel-retaining members have coplanar side surfaces forming with the flat outer surfaces of the cover member a substantially tubular envelope providing the eflfect of a tubular framing member with said panels recessed in the sides of the framing members.

18. An insulated curtain wall construction comprising horizontal and vertical members interconnected to form a frame, with each frame member having a longitudinal mounting groove and means disposed on either side of said mounting groove to support insulating glazing strips, an insulating connector member having a first portion locked within said mounting groove and a second portion extending outwardly of said mounting groove and having formed on its distal end means for adjustably securing thereto a panel-retaining member, a panel-retaining member adjustably secured to said second portion of said connector member, said panel-retaining member having means formed on opposite longitudinal edges thereof to support insulating glazing strips, a panel disposed between said horizontal and vertical members and said panel-retaining members, and insulating glazing material disposed between said panel and said frame members and between said panel and said panel-retaining members.

19. An insulated curtain wall construction according to claim 18, wherein said panel-retaining member has means formed thereon for supporting a cover member and a channel-shaped cover member is aflixed to said cover member supporting means.

20. An insulated curtain wall construction according to claim 19, wherein said horizontal and vertical members are each comprised of an elongated structural memher having a longitudinally extending channel-shaped stiffening portion that carries thereon a longitudinally extending panel-backing portion, and said panel-backing portion comprises a pair of flange members extending from said stiffening portion and defining therebetween said longitudinal mounting groove for receiving and retaining therein said first portion of said insulating connector member, said flanges having formed on the free ends thereof said means to support insulating glazing strips adjacent the longitudinal edges of said mounting groove.

21. An insulated curtain wall construction comprising horizontal and vertical members interconnected to form a frame, with each frame member being comprised of an elongated structural member having a stiffening portion that carries thereon a longitudinally extending panel-backing portion, and said panel-backing portion comprises a pair of flange members extending from said stiffening portion and defining therebetween a longitudinally extending mounting groove, said flanges having formed on the free ends thereof means to support insulating glazing strips, a longitudinally extending spring clip supported within said mounting groove in locking engagement with an insulating connector member, said insulating connector member comprising a longitudinally extending member having a first portion in interlocking engagement with said spring clip and a second portion extending outwardly of said mounting groove and having means formed on its distal end for adjustably securing thereto a panel-retaining member, a panel-retaining member adjustably secured to said second portion of said connector member, said panel-retaining member having means formed on opposite longitudinal edges thereof to support insulating glazing strips, a panel disposed between said horizontal and vertical members and said panel-retaining members, and insulating glazing material disposed between said panel and said frame members and between said panel and said panel-retaining members.

22. An insulated curtain wall construction according to claim 21, wherein said panel-retaining member has means formed thereon for supporting a. cover member and a channel-shaped cover member is aflixed to said cover member supporting means.

References Cited UNITED STATES PATENTS 1,227,861 5/1917 Waugh 52-395 1,832,847 11/1931 Lane 52403 2,842,073 7/1958 Huston et al. 52495X 2,901,785 9/1959 Hinchliffe, et al. 52395 2,956,314 10/1960 Rowe et al. 52463X 2,985,263 5/1961 Maciunas 52730X 3,052,330 9/1962 Hammitt et al. 52-464X 3,093,217 6/1963 Doede 52495X 3,309,122 3/1967 Van Der Sluys et al. 52395G 3,336,707 8/1967 Horgan, Jr. 52--395X 3,367,077 2/1968 Johnston 52395X FOREIGN PATIENTS 632,393 1/1962 Italy 52-282 69,594 7/1915 Switzerland 52463 OTHER REFERENCES 1,064,228, 81959 German Printed Application 52- 463.

ALPRED C. PERHAM, Primary Examiner US. Cl. X.R. 

